Fix 2525: check all parent interfaces for overriden methods

[ntrel]

Reboot of #12232.

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Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	2525	normal	Can't use `override` when implementing abstract base class's interface function
✓	21321	regression	Class with unimplemented interface method compiles, links, then segfaults, if inherited through abstract base class

⚠️⚠️⚠️ Warnings ⚠️⚠️⚠️

• Regression or critical bug fixes should always target the stable branch. Learn more about rebasing to stable or the D release process.

To target stable perform these two steps:

1. Rebase your branch to upstream/stable:

git rebase --onto upstream/stable upstream/master

2. Change the base branch of your PR to stable

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub run digger -- build "master + dmd#14853"

[RazvanN7]

Looks like this still needs some phobos updates.

[RazvanN7]

Also, is https://issues.dlang.org/show_bug.cgi?id=21321 a dupe of 2525? Is 21321 going to get fixed by this patch? (I assume so)

[ntrel]

I don't understand why this triggers another error in phobos:

std/traits.d(5665): Error: function `@safe void std.traits.__unittest_L5602_C7.DerivF.test2()` does not override any function, did you mean to override `@trusted void std.traits.__unittest_L5602_C7.BaseF.test2()`?

That's when overriding an interface method inside a derived interface.

[dkorpel]

@ntrel What's the status of this?

[MrcSnm]

@dkorpel Could you take a look into that? I know that D people aren't that worried about GC and classes, but I believe the OOP part should be pretty solid by now (specially since having this problem could be a bad surprise from ppl coming from other OOP languages).

[dkorpel]

Sure, unless @ntrel plans to continue this work soon?